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如果我对这个 if 语句做错了什么，我会很伤心......

我正在比较两个 indexPaths，旧的一个和当前选择的一个，如果它们不相等我想做一些其他明智的事情继续正常..

但是我的 if 语句总是被访问，即使它们是 !=.. 我做错了什么.. 我知道你可以检查 IsEqual: 这里是不是类似的东西！=？

这是我的代码和输出

NSLog(@"%@", modelIndexPath);
            NSLog(@"%@", oldCheckedIndexPath);
            NSLog(@"%@", indexPath);
            if (modelIndexPath != indexPath) {
                NSLog(@"Not Equal");
                NSLog(@" ");
            }

2012-01-19 16:09:06.521 Code[9907:207] (null)
2012-01-19 16:09:06.522 Code[9907:207] (null)
2012-01-19 16:09:06.523 Code[9907:207] <NSIndexPath 0xc2993e0> 2 indexes [9, 0]
2012-01-19 16:09:06.524 Code[9907:207] Not Equal
2012-01-19 16:09:06.525 Code[9907:207]  
2012-01-19 16:09:17.921 Code[9907:207] <NSIndexPath 0xc2993e0> 2 indexes [9, 0]
2012-01-19 16:09:17.922 Code[9907:207] <NSIndexPath 0xc2993e0> 2 indexes [9, 0]
2012-01-19 16:09:17.923 Code[9907:207] <NSIndexPath 0xc5b0c50> 2 indexes [9, 0]
2012-01-19 16:09:17.924 Code[9907:207] Not Equal
2012-01-19 16:09:17.925 Code[9907:207]  
2012-01-19 16:09:29.489 Code[9907:207] <NSIndexPath 0xc5b0c50> 2 indexes [9, 0]
2012-01-19 16:09:29.490 Code[9907:207] <NSIndexPath 0xc5b0c50> 2 indexes [9, 0]
2012-01-19 16:09:29.491 Code[9907:207] <NSIndexPath 0xc7886c0> 2 indexes [9, 2]
2012-01-19 16:09:29.491 Code[9907:207] Not Equal
2012-01-19 16:09:29.492 Code[9907:207]  
2012-01-19 16:09:34.945 Code[9907:207] <NSIndexPath 0xc7886c0> 2 indexes [9, 2]
2012-01-19 16:09:34.946 Code[9907:207] <NSIndexPath 0xc7886c0> 2 indexes [9, 2]
2012-01-19 16:09:34.946 Code[9907:207] <NSIndexPath 0xc89e780> 2 indexes [9, 2]
2012-01-19 16:09:34.947 Code[9907:207] Not Equal
2012-01-19 16:09:34.948 Code[9907:207]  
2012-01-19 16:09:37.601 Code[9907:207] <NSIndexPath 0xc89e780> 2 indexes [9, 2]
2012-01-19 16:09:37.602 Code[9907:207] <NSIndexPath 0xc89e780> 2 indexes [9, 2]
2012-01-19 16:09:37.602 Code[9907:207] <NSIndexPath 0xc94e480> 2 indexes [9, 1]
2012-01-19 16:09:37.603 Code[9907:207] Not Equal
2012-01-19 16:09:37.604 Code[9907:207]

更新：

在你们的帮助下，这是目前的状况

NSLog(@"%@", modelIndexPath);
            NSLog(@"%@", oldCheckedIndexPath);
            NSLog(@"%@", indexPath);

            if ( [modelIndexPath isEqual:indexPath] ) NSLog(@"hurray!");
            if ( ![modelIndexPath isEqual:indexPath] ) NSLog(@"bummer");
            NSLog(@" ");



2012-01-19 16:41:54.853 Code[11071:207] (null)
2012-01-19 16:41:54.854 Code[11071:207] (null)
2012-01-19 16:41:54.855 Code[11071:207] <NSIndexPath 0xc21f9a0> 2 indexes [9, 0]
2012-01-19 16:41:54.856 Code[11071:207] bummer
2012-01-19 16:41:54.856 Code[11071:207]  
2012-01-19 16:41:59.637 Code[11071:207] <NSIndexPath 0xc21f9a0> 2 indexes [9, 0]
2012-01-19 16:41:59.637 Code[11071:207] <NSIndexPath 0xc21f9a0> 2 indexes [9, 0]
2012-01-19 16:41:59.638 Code[11071:207] <NSIndexPath 0x6a73e10> 2 indexes [9, 0]
2012-01-19 16:41:59.639 Code[11071:207] hurray!
2012-01-19 16:41:59.639 Code[11071:207]  
2012-01-19 16:42:05.492 Code[11071:207] <NSIndexPath 0x6a73e10> 2 indexes [9, 0]
2012-01-19 16:42:05.493 Code[11071:207] <NSIndexPath 0x6a73e10> 2 indexes [9, 0]
2012-01-19 16:42:05.494 Code[11071:207] <NSIndexPath 0x6aae9d0> 2 indexes [9, 0]
2012-01-19 16:42:05.494 Code[11071:207] hurray!
2012-01-19 16:42:05.495 Code[11071:207]  
2012-01-19 16:42:10.901 Code[11071:207] <NSIndexPath 0x6aae9d0> 2 indexes [9, 0]
2012-01-19 16:42:10.902 Code[11071:207] <NSIndexPath 0x6aae9d0> 2 indexes [9, 0]
2012-01-19 16:42:10.902 Code[11071:207] <NSIndexPath 0xc625470> 2 indexes [9, 2]
2012-01-19 16:42:10.903 Code[11071:207] bummer
4

4 回答 4

4

NSIndexPath 是对象，使用比较它们

if (![modelIndexPath isEqual:indexPath])

编辑：也许发布更多代码，上面的代码应该没问题，或者你也可以这样做，（无论如何取决于你的需要）

int modelRow = [modelIndexPath row];
int indexRow = [indexPath row];

if (modelRow != indexRow)
{
    // Do something here
}

请注意，这仅根据您的需要起作用！

于 2012-01-19T03:22:05.610 回答
2

这些NSIndexPath东西是对象，您正在比较它们的内存地址。换句话说，两者modelIndexPath和indexPath都是指针。（谷歌是你的朋友）

要比较这些对象，请使用：

if ( [modelIndexPath isEqual:indexPath] ) NSLog(@"hurray!");

或者

if ( ![modelIndexPath isEqual:indexPath] ) NSLog(@"bummer");

来检验不等式。

于 2012-01-19T03:21:43.930 回答
1

您正在比较实例地址。采用if (![modelIndexPath isEqual:indexPath]) { //...

于 2012-01-19T03:21:58.610 回答
1

使用isEqual:而不是==

==表示如果两个引用指向同一个对象

isEqual:反对的手段是平等的

if ([modelIndexPath isEqual: indexPath]) {
                NSLog(@"Not Equal");
                NSLog(@" ");
            }
于 2012-01-19T03:23:01.883 回答